The purpose of the proposed work is to consider similarities and differences in childhood health and developmental outcomes across the UK and US. The proposed work will examine explanations for observed patterns in childhood health and development in UK and US settings. Little cross national comparative work has been carried out in this area, but with the availability of similar national data collections in the US and UK such comparative work is now possible. The proposed work will make a unique contribution to research on ethnic/racial disparities in early childhood health and development, and the findings will have strong implications in the US and UK across a range of policy settings. Specific aims of the proposed work are: 1.Describing the patterning of ethnic/racial disparities in child health and development in the US and UK; 2- Examining factors that might explain ethnic/racial disparities at an individual level; 3.Examining explanations for ethnic/racial disparities at a macro-level. We will be using national data from the Early Childhood Longitudinal Study-Birth Cohort (ECLS-B) collected on 14,000 children who were born in the US in 2001and the national Millennium Cohort Study (MCS) that was collected on 18,819 children who were born in the UK in 2001-2002. Due to the emergence of rigorous analytic techniques that can test complicated models (e.g., structural equation models, latent growth curve models) a more complete understanding of the interaction of psychological and contextual factors is possible. Our ability to test and find these pathways is important to the research we do but also ultimately to the type of interventions and policies that can be formulated to address social disparities in child health and development.